Bonding process for dielectric isolation of single crystal semiconductor structures

Claim 1

A BONDING PROCESS FOR DIELECTRICALLY ISOLATED SINGLE CRYSTAL SILICON STRUCTURES COMPRISING THE STEPS OF PROVIDING FIRST AND SECOND SINGLE CRUSTAL SILICON STRUCTURES. FORMING A SILICON DIOXIDE INSULATING LAYER ON AT LEAST ONE OF SAID SILICON STRUCTURES, CHEMICALLY DEPOSING ON AT LEAST ONE OF SAID SILICON STRUTURES AS SO PREPARED A GLASS BONDING LAYER CONSISTING ESSENTIALLY IN MOLE PERCENT OF 15-20 PERCENT BORIC OXIDE AND 80-85 PERCENT SILICON DIOXIDE AND HAVING A THERMAL EXPANSION COEFFICIENT THAT APPROSIMATELY MATCHES THE THERMAL EXPANSION COEFFICIENT OF SILICON, AND BONDING TOGETHER SAID SINGLE CRYSTAL SILICON STRUCTURES WITH AT LEAST ONE INTERMEDIATE SILICON DIOXIDE LAYER AND GLASS BONDING LAYER AT A TEMPERATURE NOT EXCEEDING ABOUT 900*C AND AT LEAST AS HIGH AS THE SOFTENING TEMPERATURE OF SAID GLASS BONDING LAYER UNDER A CONTROLLED PRESSURE OF SEVERAL HUNDRED PSI AND FOR A TIME INTERVAL OF ABOUT ONE HALF HOUR TO 1 HOUR TO THEREBY CAUSE FLOW OF SAID GLASS BONDING LAYER UNDER THE CONTROLLED PRESSURE.